Floor covering sheets and tiles are bonded to concrete floor surfaces in industrial and manufacturing facilities to provide a dust-free surface which can be easily cleaned and maintained. The most conventional sheets and tiles are made with vinyl polymers and are commonly references as vinyl sheet and tiles. Moisture collection under the vinyl floor coverings, particularly on newly formed concrete, causes delamination of the vinyl to floor bond and formation of large raised surface areas or bubbles along the vinyl surface. Moisture collection occurs when the water vapor emitted from each area of the concrete surface exceeds the maximum moisture diffusion rate of the floor covering for that area. The maximum moisture emission rating for conventional vinyl sheets and mastic floor coverings is usually up to about 3 to 4 pounds of water vapor per 24 hours per 1000 square feet of vinyl sheet (4 lbs. water/1000 sq.ft./24 hrs.).
Prior methods for applying vinyl flooring materials generally involve the application of an adhesive mastic directly to the concrete surface and the placement of the vinyl sheeting and tiles directly to the adhesive layer. We have discovered a previously unrecognized cause of separation of these floor coverings from the underlying surface. Moisture emitted from each portion of the floor surface must pass upwardly through the adhesive layer and tile to escape, and localized emissions exceeding the rating of the floor covering causes a collection of condensate, delamination and bubbling. These causes of floor covering failures have continued to be a serious problem until the development of the methods and products of this invention.